1 //===-- DynamicLoaderPOSIX.h ------------------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 // C Includes
11 // C++ Includes
12 // Other libraries and framework includes
13 #include "lldb/Core/PluginManager.h"
14 #include "lldb/Core/Log.h"
15 #include "lldb/Core/Module.h"
16 #include "lldb/Core/ModuleSpec.h"
17 #include "lldb/Core/Section.h"
18 #include "lldb/Symbol/ObjectFile.h"
19 #include "lldb/Target/Process.h"
20 #include "lldb/Target/Target.h"
21 #include "lldb/Target/Thread.h"
22 #include "lldb/Target/ThreadPlanRunToAddress.h"
23 #include "lldb/Breakpoint/BreakpointLocation.h"
24 
25 #include "AuxVector.h"
26 #include "DynamicLoaderPOSIXDYLD.h"
27 
28 using namespace lldb;
29 using namespace lldb_private;
30 
31 void
Initialize()32 DynamicLoaderPOSIXDYLD::Initialize()
33 {
34     PluginManager::RegisterPlugin(GetPluginNameStatic(),
35                                   GetPluginDescriptionStatic(),
36                                   CreateInstance);
37 }
38 
39 void
Terminate()40 DynamicLoaderPOSIXDYLD::Terminate()
41 {
42 }
43 
44 lldb_private::ConstString
GetPluginName()45 DynamicLoaderPOSIXDYLD::GetPluginName()
46 {
47     return GetPluginNameStatic();
48 }
49 
50 lldb_private::ConstString
GetPluginNameStatic()51 DynamicLoaderPOSIXDYLD::GetPluginNameStatic()
52 {
53     static ConstString g_name("linux-dyld");
54     return g_name;
55 }
56 
57 const char *
GetPluginDescriptionStatic()58 DynamicLoaderPOSIXDYLD::GetPluginDescriptionStatic()
59 {
60     return "Dynamic loader plug-in that watches for shared library "
61            "loads/unloads in POSIX processes.";
62 }
63 
64 void
GetPluginCommandHelp(const char * command,Stream * strm)65 DynamicLoaderPOSIXDYLD::GetPluginCommandHelp(const char *command, Stream *strm)
66 {
67 }
68 
69 uint32_t
GetPluginVersion()70 DynamicLoaderPOSIXDYLD::GetPluginVersion()
71 {
72     return 1;
73 }
74 
75 DynamicLoader *
CreateInstance(Process * process,bool force)76 DynamicLoaderPOSIXDYLD::CreateInstance(Process *process, bool force)
77 {
78     bool create = force;
79     if (!create)
80     {
81         const llvm::Triple &triple_ref = process->GetTarget().GetArchitecture().GetTriple();
82         if (triple_ref.getOS() == llvm::Triple::Linux ||
83             triple_ref.getOS() == llvm::Triple::FreeBSD)
84             create = true;
85     }
86 
87     if (create)
88         return new DynamicLoaderPOSIXDYLD (process);
89     return NULL;
90 }
91 
DynamicLoaderPOSIXDYLD(Process * process)92 DynamicLoaderPOSIXDYLD::DynamicLoaderPOSIXDYLD(Process *process)
93     : DynamicLoader(process),
94       m_rendezvous(process),
95       m_load_offset(LLDB_INVALID_ADDRESS),
96       m_entry_point(LLDB_INVALID_ADDRESS),
97       m_auxv(),
98       m_dyld_bid(LLDB_INVALID_BREAK_ID)
99 {
100 }
101 
~DynamicLoaderPOSIXDYLD()102 DynamicLoaderPOSIXDYLD::~DynamicLoaderPOSIXDYLD()
103 {
104     if (m_dyld_bid != LLDB_INVALID_BREAK_ID)
105     {
106         m_process->GetTarget().RemoveBreakpointByID (m_dyld_bid);
107         m_dyld_bid = LLDB_INVALID_BREAK_ID;
108     }
109 }
110 
111 void
DidAttach()112 DynamicLoaderPOSIXDYLD::DidAttach()
113 {
114     ModuleSP executable;
115     addr_t load_offset;
116 
117     m_auxv.reset(new AuxVector(m_process));
118 
119     executable = GetTargetExecutable();
120     load_offset = ComputeLoadOffset();
121 
122     if (executable.get() && load_offset != LLDB_INVALID_ADDRESS)
123     {
124         ModuleList module_list;
125         module_list.Append(executable);
126         UpdateLoadedSections(executable, LLDB_INVALID_ADDRESS, load_offset);
127         LoadAllCurrentModules();
128         m_process->GetTarget().ModulesDidLoad(module_list);
129     }
130 }
131 
132 void
DidLaunch()133 DynamicLoaderPOSIXDYLD::DidLaunch()
134 {
135     ModuleSP executable;
136     addr_t load_offset;
137 
138     m_auxv.reset(new AuxVector(m_process));
139 
140     executable = GetTargetExecutable();
141     load_offset = ComputeLoadOffset();
142 
143     if (executable.get() && load_offset != LLDB_INVALID_ADDRESS)
144     {
145         ModuleList module_list;
146         module_list.Append(executable);
147         UpdateLoadedSections(executable, LLDB_INVALID_ADDRESS, load_offset);
148         ProbeEntry();
149         m_process->GetTarget().ModulesDidLoad(module_list);
150     }
151 }
152 
153 Error
ExecutePluginCommand(Args & command,Stream * strm)154 DynamicLoaderPOSIXDYLD::ExecutePluginCommand(Args &command, Stream *strm)
155 {
156     return Error();
157 }
158 
159 Log *
EnablePluginLogging(Stream * strm,Args & command)160 DynamicLoaderPOSIXDYLD::EnablePluginLogging(Stream *strm, Args &command)
161 {
162     return NULL;
163 }
164 
165 Error
CanLoadImage()166 DynamicLoaderPOSIXDYLD::CanLoadImage()
167 {
168     return Error();
169 }
170 
171 void
UpdateLoadedSections(ModuleSP module,addr_t link_map_addr,addr_t base_addr)172 DynamicLoaderPOSIXDYLD::UpdateLoadedSections(ModuleSP module, addr_t link_map_addr, addr_t base_addr)
173 {
174     m_loaded_modules[module] = link_map_addr;
175 
176     UpdateLoadedSectionsCommon(module, base_addr);
177 }
178 
179 void
UnloadSections(const ModuleSP module)180 DynamicLoaderPOSIXDYLD::UnloadSections(const ModuleSP module)
181 {
182     m_loaded_modules.erase(module);
183 
184     UnloadSectionsCommon(module);
185 }
186 
187 void
ProbeEntry()188 DynamicLoaderPOSIXDYLD::ProbeEntry()
189 {
190     Breakpoint *entry_break;
191     addr_t entry;
192 
193     if ((entry = GetEntryPoint()) == LLDB_INVALID_ADDRESS)
194         return;
195 
196     entry_break = m_process->GetTarget().CreateBreakpoint(entry, true, false).get();
197     entry_break->SetCallback(EntryBreakpointHit, this, true);
198     entry_break->SetBreakpointKind("shared-library-event");
199 }
200 
201 // The runtime linker has run and initialized the rendezvous structure once the
202 // process has hit its entry point.  When we hit the corresponding breakpoint we
203 // interrogate the rendezvous structure to get the load addresses of all
204 // dependent modules for the process.  Similarly, we can discover the runtime
205 // linker function and setup a breakpoint to notify us of any dynamically loaded
206 // modules (via dlopen).
207 bool
EntryBreakpointHit(void * baton,StoppointCallbackContext * context,user_id_t break_id,user_id_t break_loc_id)208 DynamicLoaderPOSIXDYLD::EntryBreakpointHit(void *baton,
209                                            StoppointCallbackContext *context,
210                                            user_id_t break_id,
211                                            user_id_t break_loc_id)
212 {
213     DynamicLoaderPOSIXDYLD* dyld_instance;
214 
215     dyld_instance = static_cast<DynamicLoaderPOSIXDYLD*>(baton);
216     dyld_instance->LoadAllCurrentModules();
217     dyld_instance->SetRendezvousBreakpoint();
218     return false; // Continue running.
219 }
220 
221 void
SetRendezvousBreakpoint()222 DynamicLoaderPOSIXDYLD::SetRendezvousBreakpoint()
223 {
224     addr_t break_addr = m_rendezvous.GetBreakAddress();
225     Target &target = m_process->GetTarget();
226 
227     if (m_dyld_bid == LLDB_INVALID_BREAK_ID)
228     {
229         Breakpoint *dyld_break = target.CreateBreakpoint (break_addr, true, false).get();
230         dyld_break->SetCallback(RendezvousBreakpointHit, this, true);
231         dyld_break->SetBreakpointKind ("shared-library-event");
232         m_dyld_bid = dyld_break->GetID();
233     }
234 
235     // Make sure our breakpoint is at the right address.
236     assert (target.GetBreakpointByID(m_dyld_bid)->FindLocationByAddress(break_addr)->GetBreakpoint().GetID() == m_dyld_bid);
237 }
238 
239 bool
RendezvousBreakpointHit(void * baton,StoppointCallbackContext * context,user_id_t break_id,user_id_t break_loc_id)240 DynamicLoaderPOSIXDYLD::RendezvousBreakpointHit(void *baton,
241                                                 StoppointCallbackContext *context,
242                                                 user_id_t break_id,
243                                                 user_id_t break_loc_id)
244 {
245     DynamicLoaderPOSIXDYLD* dyld_instance;
246 
247     dyld_instance = static_cast<DynamicLoaderPOSIXDYLD*>(baton);
248     dyld_instance->RefreshModules();
249 
250     // Return true to stop the target, false to just let the target run.
251     return dyld_instance->GetStopWhenImagesChange();
252 }
253 
254 void
RefreshModules()255 DynamicLoaderPOSIXDYLD::RefreshModules()
256 {
257     if (!m_rendezvous.Resolve())
258         return;
259 
260     DYLDRendezvous::iterator I;
261     DYLDRendezvous::iterator E;
262 
263     ModuleList &loaded_modules = m_process->GetTarget().GetImages();
264 
265     if (m_rendezvous.ModulesDidLoad())
266     {
267         ModuleList new_modules;
268 
269         E = m_rendezvous.loaded_end();
270         for (I = m_rendezvous.loaded_begin(); I != E; ++I)
271         {
272             FileSpec file(I->path.c_str(), true);
273             ModuleSP module_sp = LoadModuleAtAddress(file, I->link_addr, I->base_addr);
274             if (module_sp.get())
275             {
276                 loaded_modules.AppendIfNeeded(module_sp);
277                 new_modules.Append(module_sp);
278             }
279         }
280         m_process->GetTarget().ModulesDidLoad(new_modules);
281     }
282 
283     if (m_rendezvous.ModulesDidUnload())
284     {
285         ModuleList old_modules;
286 
287         E = m_rendezvous.unloaded_end();
288         for (I = m_rendezvous.unloaded_begin(); I != E; ++I)
289         {
290             FileSpec file(I->path.c_str(), true);
291             ModuleSpec module_spec (file);
292             ModuleSP module_sp =
293                 loaded_modules.FindFirstModule (module_spec);
294 
295             if (module_sp.get())
296             {
297                 old_modules.Append(module_sp);
298                 UnloadSections(module_sp);
299             }
300         }
301         loaded_modules.Remove(old_modules);
302         m_process->GetTarget().ModulesDidUnload(old_modules, false);
303     }
304 }
305 
306 ThreadPlanSP
GetStepThroughTrampolinePlan(Thread & thread,bool stop)307 DynamicLoaderPOSIXDYLD::GetStepThroughTrampolinePlan(Thread &thread, bool stop)
308 {
309     ThreadPlanSP thread_plan_sp;
310 
311     StackFrame *frame = thread.GetStackFrameAtIndex(0).get();
312     const SymbolContext &context = frame->GetSymbolContext(eSymbolContextSymbol);
313     Symbol *sym = context.symbol;
314 
315     if (sym == NULL || !sym->IsTrampoline())
316         return thread_plan_sp;
317 
318     const ConstString &sym_name = sym->GetMangled().GetName(Mangled::ePreferMangled);
319     if (!sym_name)
320         return thread_plan_sp;
321 
322     SymbolContextList target_symbols;
323     Target &target = thread.GetProcess()->GetTarget();
324     const ModuleList &images = target.GetImages();
325 
326     images.FindSymbolsWithNameAndType(sym_name, eSymbolTypeCode, target_symbols);
327     size_t num_targets = target_symbols.GetSize();
328     if (!num_targets)
329         return thread_plan_sp;
330 
331     typedef std::vector<lldb::addr_t> AddressVector;
332     AddressVector addrs;
333     for (size_t i = 0; i < num_targets; ++i)
334     {
335         SymbolContext context;
336         AddressRange range;
337         if (target_symbols.GetContextAtIndex(i, context))
338         {
339             context.GetAddressRange(eSymbolContextEverything, 0, false, range);
340             lldb::addr_t addr = range.GetBaseAddress().GetLoadAddress(&target);
341             if (addr != LLDB_INVALID_ADDRESS)
342                 addrs.push_back(addr);
343         }
344     }
345 
346     if (addrs.size() > 0)
347     {
348         AddressVector::iterator start = addrs.begin();
349         AddressVector::iterator end = addrs.end();
350 
351         std::sort(start, end);
352         addrs.erase(std::unique(start, end), end);
353         thread_plan_sp.reset(new ThreadPlanRunToAddress(thread, addrs, stop));
354     }
355 
356     return thread_plan_sp;
357 }
358 
359 void
LoadAllCurrentModules()360 DynamicLoaderPOSIXDYLD::LoadAllCurrentModules()
361 {
362     DYLDRendezvous::iterator I;
363     DYLDRendezvous::iterator E;
364     ModuleList module_list;
365 
366     if (!m_rendezvous.Resolve())
367     {
368         Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
369         if (log)
370             log->Printf("DynamicLoaderPOSIXDYLD::%s unable to resolve POSIX DYLD rendezvous address",
371                         __FUNCTION__);
372         return;
373     }
374 
375     // The rendezvous class doesn't enumerate the main module, so track
376     // that ourselves here.
377     ModuleSP executable = GetTargetExecutable();
378     m_loaded_modules[executable] = m_rendezvous.GetLinkMapAddress();
379 
380 
381     for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I)
382     {
383         const char *module_path = I->path.c_str();
384         FileSpec file(module_path, false);
385         ModuleSP module_sp = LoadModuleAtAddress(file, I->link_addr, I->base_addr);
386 #ifdef __FreeBSD__ // llvm.org/pr17880
387         if (module_sp == executable)
388         {
389             Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
390             if (log)
391                 log->Printf("DynamicLoaderPOSIXDYLD::%s reloading main module, ignoring rendezvous base addr %" PRIx64,
392                             __FUNCTION__, I->base_addr);
393             ModuleSP module_sp = LoadModuleAtAddress(file, I->link_addr, 0);
394         }
395 #endif
396 
397         if (module_sp.get())
398         {
399             module_list.Append(module_sp);
400         }
401         else
402         {
403             Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
404             if (log)
405                 log->Printf("DynamicLoaderPOSIXDYLD::%s failed loading module %s at 0x%" PRIx64,
406                             __FUNCTION__, module_path, I->base_addr);
407         }
408     }
409 
410     m_process->GetTarget().ModulesDidLoad(module_list);
411 }
412 
413 addr_t
ComputeLoadOffset()414 DynamicLoaderPOSIXDYLD::ComputeLoadOffset()
415 {
416     addr_t virt_entry;
417 
418     if (m_load_offset != LLDB_INVALID_ADDRESS)
419         return m_load_offset;
420 
421     if ((virt_entry = GetEntryPoint()) == LLDB_INVALID_ADDRESS)
422         return LLDB_INVALID_ADDRESS;
423 
424     ModuleSP module = m_process->GetTarget().GetExecutableModule();
425     if (!module)
426         return LLDB_INVALID_ADDRESS;
427 
428     ObjectFile *exe = module->GetObjectFile();
429     Address file_entry = exe->GetEntryPointAddress();
430 
431     if (!file_entry.IsValid())
432         return LLDB_INVALID_ADDRESS;
433 
434     m_load_offset = virt_entry - file_entry.GetFileAddress();
435     return m_load_offset;
436 }
437 
438 addr_t
GetEntryPoint()439 DynamicLoaderPOSIXDYLD::GetEntryPoint()
440 {
441     if (m_entry_point != LLDB_INVALID_ADDRESS)
442         return m_entry_point;
443 
444     if (m_auxv.get() == NULL)
445         return LLDB_INVALID_ADDRESS;
446 
447     AuxVector::iterator I = m_auxv->FindEntry(AuxVector::AT_ENTRY);
448 
449     if (I == m_auxv->end())
450         return LLDB_INVALID_ADDRESS;
451 
452     m_entry_point = static_cast<addr_t>(I->value);
453     return m_entry_point;
454 }
455 
456 lldb::addr_t
GetThreadLocalData(const lldb::ModuleSP module,const lldb::ThreadSP thread)457 DynamicLoaderPOSIXDYLD::GetThreadLocalData (const lldb::ModuleSP module, const lldb::ThreadSP thread)
458 {
459     auto it = m_loaded_modules.find (module);
460     if (it == m_loaded_modules.end())
461         return LLDB_INVALID_ADDRESS;
462 
463     addr_t link_map = it->second;
464     if (link_map == LLDB_INVALID_ADDRESS)
465         return LLDB_INVALID_ADDRESS;
466 
467     const DYLDRendezvous::ThreadInfo &metadata = m_rendezvous.GetThreadInfo();
468     if (!metadata.valid)
469         return LLDB_INVALID_ADDRESS;
470 
471     // Get the thread pointer.
472     addr_t tp = thread->GetThreadPointer ();
473     if (tp == LLDB_INVALID_ADDRESS)
474         return LLDB_INVALID_ADDRESS;
475 
476     // Find the module's modid.
477     int modid_size = 4;  // FIXME(spucci): This isn't right for big-endian 64-bit
478     int64_t modid = ReadUnsignedIntWithSizeInBytes (link_map + metadata.modid_offset, modid_size);
479     if (modid == -1)
480         return LLDB_INVALID_ADDRESS;
481 
482     // Lookup the DTV stucture for this thread.
483     addr_t dtv_ptr = tp + metadata.dtv_offset;
484     addr_t dtv = ReadPointer (dtv_ptr);
485     if (dtv == LLDB_INVALID_ADDRESS)
486         return LLDB_INVALID_ADDRESS;
487 
488     // Find the TLS block for this module.
489     addr_t dtv_slot = dtv + metadata.dtv_slot_size*modid;
490     addr_t tls_block = ReadPointer (dtv_slot + metadata.tls_offset);
491 
492     Module *mod = module.get();
493     Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
494     if (log)
495         log->Printf("DynamicLoaderPOSIXDYLD::Performed TLS lookup: "
496                     "module=%s, link_map=0x%" PRIx64 ", tp=0x%" PRIx64 ", modid=%" PRId64 ", tls_block=0x%" PRIx64 "\n",
497                     mod->GetObjectName().AsCString(""), link_map, tp, (int64_t)modid, tls_block);
498 
499     return tls_block;
500 }
501